If you want to increase the size of the display of the font in the Find window, use the View:Zoom In menu.
If you increase the size of the font in the Find window, the search becomes Attribute Sensitive; then only find strings with that increased font size in the document will be found.

enaid1 wrote:Do either of you know how this happened in the first place, so I don't end up doing it again?

Generally speaking the Find dialog will assume the font/size of the frontmost document. So if your document has a tiny font, the find dialog will also use a tiny font. So there's probably nothing you did directly to trigger this, it's just the documents you're working with now.

And as Hamid said, using the normal zoom in/out menus (or their keyboard shortcuts) are the best way to solve this.